/*  
 *  Copyright 2007-2008 Lawrence Beadle & Tom Castle
 *  Licensed under GNU General Public License
 * 
 *  This file is part of EpochX: genetic programming for research
 *
 *  EpochX is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  EpochX is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 * 
 *  You should have received a copy of the GNU General Public License
 *  along with EpochX.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.epochx.random;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.Serializable;
import java.util.Random;

/**
 * Taken from ECJ.
 * 
 * <h3>MersenneTwister and MersenneTwisterFast</h3>
 * <p><b>Version 13</b>, based on version MT199937(99/10/29)
 * of the Mersenne Twister algorithm found at
 * <a href="http://www.math.keio.ac.jp/matumoto/emt.html">
 * The Mersenne Twister Home Page</a>, with the initialization
 * improved using the new 2002/1/26 initialization algorithm
 * By Sean Luke, October 2004.
 *
 * <p><b>MersenneTwister</b> is a drop-in subclass replacement
 * for java.util.Random.  It is properly synchronized and
 * can be used in a multithreaded environment.  On modern VMs such
 * as HotSpot, it is approximately 1/3 slower than java.util.Random.
 *
 * <p><b>MersenneTwisterFast</b> is not a subclass of java.util.Random.  It has
 * the same public methods as Random does, however, and it is
 * algorithmically identical to MersenneTwister.  MersenneTwisterFast
 * has hard-code inlined all of its methods directly, and made all of them
 * final (well, the ones of consequence anyway).  Further, these
 * methods are <i>not</i> synchronized, so the same MersenneTwisterFast
 * instance cannot be shared by multiple threads.  But all this helps
 * MersenneTwisterFast achieve well over twice the speed of MersenneTwister.
 * java.util.Random is about 1/3 slower than MersenneTwisterFast.
 *
 * <h3>About the Mersenne Twister</h3>
 * <p>This is a Java version of the C-program for MT19937: Integer version.
 * The MT19937 algorithm was created by Makoto Matsumoto and Takuji Nishimura,
 * who ask: "When you use this, send an email to: matumoto@math.keio.ac.jp
 * with an appropriate reference to your work".  Indicate that this
 * is a translation of their algorithm into Java.
 *
 * <p><b>Reference. </b>
 * Makato Matsumoto and Takuji Nishimura,
 * "Mersenne Twister: A 623-Dimensionally Equidistributed Uniform
 * Pseudo-Random Number Generator",
 * <i>ACM Transactions on Modeling and. Computer Simulation,</i>
 * Vol. 8, No. 1, January 1998, pp 3--30.
 *
 * <h3>About this Version</h3>
 *
 * <p><b>Changes Since V12:</b> clone() method added.
 *
 * <p><b>Changes Since V11:</b> stateEquals(...) method added.  MersenneTwisterFast
 * is equal to other MersenneTwisterFasts with identical state; likewise
 * MersenneTwister is equal to other MersenneTwister with identical state.
 * This isn't equals(...) because that requires a contract of immutability
 * to compare by value.
 *
 * <p><b>Changes Since V10:</b> A documentation error suggested that
 * setSeed(int[]) required an int[] array 624 long.  In fact, the array
 * can be any non-zero length.  The new version also checks for this fact.
 *
 * <p><b>Changes Since V9:</b> readState(stream) and writeState(stream)
 * provided.
 *
 * <p><b>Changes Since V8:</b> setSeed(int) was only using the first 28 bits
 * of the seed; it should have been 32 bits.  For small-number seeds the
 * behavior is identical.
 *
 * <p><b>Changes Since V7:</b> A documentation error in MersenneTwisterFast
 * (but not MersenneTwister) stated that nextDouble selects uniformly from
 * the full-open interval [0,1].  It does not.  nextDouble's contract is
 * identical across MersenneTwisterFast, MersenneTwister, and java.util.Random,
 * namely, selection in the half-open interval [0,1).  That is, 1.0 should
 * not be returned.  A similar contract exists in nextFloat.
 *
 * <p><b>Changes Since V6:</b> License has changed from LGPL to BSD.
 * New timing information to compare against
 * java.util.Random.  Recent versions of HotSpot have helped Random increase
 * in speed to the point where it is faster than MersenneTwister but slower
 * than MersenneTwisterFast (which should be the case, as it's a less complex
 * algorithm but is synchronized).
 *
 * <p><b>Changes Since V5:</b> New empty constructor made to work the same
 * as java.util.Random -- namely, it seeds based on the current time in
 * milliseconds.
 *
 * <p><b>Changes Since V4:</b> New initialization algorithms.  See
 * (see <a href="http://www.math.keio.ac.jp/matumoto/MT2002/emt19937ar.html"</a>
 * http://www.math.keio.ac.jp/matumoto/MT2002/emt19937ar.html</a>)
 *
 * <p>The MersenneTwister code is based on standard MT19937 C/C++
 * code by Takuji Nishimura,
 * with suggestions from Topher Cooper and Marc Rieffel, July 1997.
 * The code was originally translated into Java by Michael Lecuyer,
 * January 1999, and the original code is Copyright (c) 1999 by Michael Lecuyer.
 *
 * <h3>Java notes</h3>
 *
 * <p>This implementation implements the bug fixes made
 * in Java 1.2's version of Random, which means it can be used with
 * earlier versions of Java.  See
 * <a href="http://www.javasoft.com/products/jdk/1.2/docs/api/java/util/Random.html">
 * the JDK 1.2 java.util.Random documentation</a> for further documentation
 * on the random-number generation contracts made.  Additionally, there's
 * an undocumented bug in the JDK java.util.Random.nextBytes() method,
 * which this code fixes.
 *
 * <p> Just like java.util.Random, this
 * generator accepts a long seed but doesn't use all of it.  java.util.Random
 * uses 48 bits.  The Mersenne Twister instead uses 32 bits (int size).
 * So it's best if your seed does not exceed the int range.
 *
 * <p>MersenneTwister can be used reliably
 * on JDK version 1.1.5 or above.  Earlier Java versions have serious bugs in
 * java.util.Random; only MersenneTwisterFast (and not MersenneTwister nor
 * java.util.Random) should be used with them.
 *
 * <h3>License</h3>
 *
 * Copyright (c) 2003 by Sean Luke. <br>
 * Portions copyright (c) 1993 by Michael Lecuyer. <br>
 * All rights reserved. <br>
 *
 * <p>Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * <ul>
 * <li> Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * <li> Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * <li> Neither the name of the copyright owners, their employers, nor the
 * names of its contributors may be used to endorse or promote products
 * derived from this software without specific prior written permission.
 * </ul>
 * <p>THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * @version 13
 */

// Note: this class is hard-inlined in all of its methods.  This makes some of
// the methods well-nigh unreadable in their complexity.  In fact, the Mersenne
// Twister is fairly easy code to understand: if you're trying to get a handle
// on the code, I strongly suggest looking at MersenneTwister.java first.
// -- Sean

public class MersenneTwisterFast implements Serializable, Cloneable, RandomNumberGenerator {
    // Period parameters
    private static final int N = 624;
    private static final int M = 397;
    private static final int MATRIX_A = 0x9908b0df;   //    private static final * constant vector a
    private static final int UPPER_MASK = 0x80000000; // most significant w-r bits
    private static final int LOWER_MASK = 0x7fffffff; // least significant r bits
    
    
    // Tempering parameters
    private static final int TEMPERING_MASK_B = 0x9d2c5680;
    private static final int TEMPERING_MASK_C = 0xefc60000;
    
    private int mt[]; // the array for the state vector
    private int mti; // mti==N+1 means mt[N] is not initialized
    private int mag01[];
    
    // a good initial seed (of int size, though stored in a long)
    //private static final long GOOD_SEED = 4357;
    
    private double __nextNextGaussian;
    private boolean __haveNextNextGaussian;
    
    /* We're overriding all internal data, to my knowledge, so this should be okay */
    public Object clone() throws CloneNotSupportedException {
        MersenneTwisterFast f = (MersenneTwisterFast)(super.clone());
        f.mt = mt.clone();
        f.mag01 = mag01.clone();
        return f;
    }
    
    public boolean stateEquals(Object o) {
        if (o==this) return true;
        if (o == null || !(o instanceof MersenneTwisterFast))
            return false;
        MersenneTwisterFast other = (MersenneTwisterFast) o;
        if (mti != other.mti) return false;
        for(int x=0;x<mag01.length;x++)
            if (mag01[x] != other.mag01[x]) return false;
        for(int x=0;x<mt.length;x++)
            if (mt[x] != other.mt[x]) return false;
        return true;
    }
    
    /** Reads the entire state of the MersenneTwister RNG from the stream
     *  @param stream input stream
     *  @throws IOException exception from stream reading
     */
    public void readState(DataInputStream stream) throws IOException {
        int len = mt.length;
        for(int x=0;x<len;x++) mt[x] = stream.readInt();
        
        len = mag01.length;
        for(int x=0;x<len;x++) mag01[x] = stream.readInt();
        
        mti = stream.readInt();
        __nextNextGaussian = stream.readDouble();
        __haveNextNextGaussian = stream.readBoolean();
    }
    
    /** Writes the entire state of the MersenneTwister RNG to the stream
     *  @param stream output stream
     *  @throws IOException exception from stream reading
     */
    public void writeState(DataOutputStream stream) throws IOException {
        int len = mt.length;
        for(int x=0;x<len;x++) stream.writeInt(mt[x]);
        
        len = mag01.length;
        for(int x=0;x<len;x++) stream.writeInt(mag01[x]);
        
        stream.writeInt(mti);
        stream.writeDouble(__nextNextGaussian);
        stream.writeBoolean(__haveNextNextGaussian);
    }
    
    /**
     * Constructor using the default seed.
     */
    public MersenneTwisterFast() {
        this(System.currentTimeMillis());
    }
    
    /**
     * Constructor using a given seed.  Though you pass this seed in
     * as a long, it's best to make sure it's actually an integer.
     * @param seed seed
     */
    public MersenneTwisterFast(final long seed) {
        setSeed(seed);
    }
    
    
    /**
     * Constructor using an array of integers as seed.
     * Your array must have a non-zero length.  Only the first 624 integers
     * in the array are used; if the array is shorter than this then
     * integers are repeatedly used in a wrap-around fashion.
     * @param array seed array
     */
    public MersenneTwisterFast(final int[] array) {
        setSeed(array);
    }
    
    
    /**
     * Initalize the pseudo random number generator.  Don't
     * pass in a long that's bigger than an int (Mersenne Twister
     * only uses the first 32 bits for its seed).
     */
    
    synchronized public void setSeed(final long seed) {
        // Due to a bug in java.util.Random clear up to 1.2, we're
        // doing our own Gaussian variable.
        __haveNextNextGaussian = false;
        
        mt = new int[N];
        
        mag01 = new int[2];
        mag01[0] = 0x0;
        mag01[1] = MATRIX_A;
        
        mt[0]= (int)(seed);
        for (mti=1; mti<N; mti++) {
            mt[mti] =
                    (1812433253 * (mt[mti-1] ^ (mt[mti-1] >>> 30)) + mti);
            /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
            /* In the previous versions, MSBs of the seed affect   */
            /* only MSBs of the array mt[].                        */
            /* 2002/01/09 modified by Makoto Matsumoto             */
            mt[mti] &= 0xffffffff;
            /* for >32 bit machines */
        }
    }
    
    
    /**
     * Sets the seed of the MersenneTwister using an array of integers.
     * Your array must have a non-zero length.  Only the first 624 integers
     * in the array are used; if the array is shorter than this then
     * integers are repeatedly used in a wrap-around fashion.
     */
    
    synchronized public void setSeed(final int[] array) {
        if (array.length == 0)
            throw new IllegalArgumentException("Array length must be greater than zero");
        int i, j, k;
        setSeed(19650218);
        i=1; j=0;
        k = (N>array.length ? N : array.length);
        for (; k!=0; k--) {
            mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >>> 30)) * 1664525)) + array[j] + j; /* non linear */
            mt[i] &= 0xffffffff; /* for WORDSIZE > 32 machines */
            i++;
            j++;
            if (i>=N) { mt[0] = mt[N-1]; i=1; }
            if (j>=array.length) j=0;
        }
        for (k=N-1; k!=0; k--) {
            mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >>> 30)) * 1566083941)) - i; /* non linear */
            mt[i] &= 0xffffffff; /* for WORDSIZE > 32 machines */
            i++;
            if (i>=N) {
                mt[0] = mt[N-1]; i=1;
            }
        }
        mt[0] = 0x80000000; /* MSB is 1; assuring non-zero initial array */
    }
    
    
    public final int nextInt() {
        int y;
        
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            for (; kk < N-1; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
            
            mti = 0;
        }
        
        y = mt[mti++];
        y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
        y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
        y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
        y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
        
        return y;
    }
    
    
    
    public final short nextShort() {
        int y;
        
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            for (; kk < N-1; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
            
            mti = 0;
        }
        
        y = mt[mti++];
        y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
        y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
        y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
        y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
        
        return (short)(y >>> 16);
    }
    
    
    
    public final char nextChar() {
        int y;
        
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            for (; kk < N-1; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
            
            mti = 0;
        }
        
        y = mt[mti++];
        y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
        y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
        y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
        y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
        
        return (char)(y >>> 16);
    }
    
    
    public final boolean nextBoolean() {
        int y;
        
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            for (; kk < N-1; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
            
            mti = 0;
        }
        
        y = mt[mti++];
        y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
        y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
        y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
        y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
        
        return (y >>> 31) != 0;
    }
    
    
    
    /** This generates a coin flip with a probability <tt>probability</tt>
     * of returning true, else returning false.  <tt>probability</tt> must
     * be between 0.0 and 1.0, inclusive.   Not as precise a random real
     * event as nextBoolean(double), but twice as fast. To explicitly
     * use this, remember you may need to cast to float first.
     * @param probability flip probability
     * @return next boolean
     */
    
    public final boolean nextBoolean(final float probability) {
        int y;
        
        if (probability < 0.0f || probability > 1.0f)
            throw new IllegalArgumentException("probability must be between 0.0 and 1.0 inclusive.");
        if (probability==0.0f) return false;            // fix half-open issues
        else if (probability==1.0f) return true;        // fix half-open issues
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            for (; kk < N-1; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
            
            mti = 0;
        }
        
        y = mt[mti++];
        y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
        y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
        y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
        y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
        
        return (y >>> 8) / ((float)(1 << 24)) < probability;
    }
    
    
    /** This generates a coin flip with a probability <tt>probability</tt>
     * of returning true, else returning false.  <tt>probability</tt> must
     * be between 0.0 and 1.0, inclusive. */
    
    @SuppressWarnings({"ConstantConditions"})
    public final boolean nextBoolean(final double probability) {
        int y;
        int z;
        
        if (probability < 0.0 || probability > 1.0)
            throw new IllegalArgumentException("probability must be between 0.0 and 1.0 inclusive.");
        if (probability==0.0) return false;             // fix half-open issues
        else if (probability==1.0) return true; // fix half-open issues
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            for (; kk < N-1; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
            
            mti = 0;
        }
        
        y = mt[mti++];
        y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
        y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
        y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
        y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
        
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                z = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (z >>> 1) ^ mag01[z & 0x1];
            }
            for (; kk < N-1; kk++) {
                z = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (z >>> 1) ^ mag01[z & 0x1];
            }
            z = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (z >>> 1) ^ mag01[z & 0x1];
            
            mti = 0;
        }
        
        z = mt[mti++];
        z ^= z >>> 11;                          // TEMPERING_SHIFT_U(z)
        z ^= (z << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(z)
        z ^= (z << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(z)
        z ^= (z >>> 18);                        // TEMPERING_SHIFT_L(z)
        
        /* derived from nextDouble documentation in jdk 1.2 docs, see top */
        return ((((long)(y >>> 6)) << 27) + (z >>> 5)) / (double)(1L << 53) < probability;
    }
    
    
    public final byte nextByte() {
        int y;
        
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            for (; kk < N-1; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
            
            mti = 0;
        }
        
        y = mt[mti++];
        y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
        y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
        y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
        y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
        
        return (byte)(y >>> 24);
    }
    
    
    public final void nextBytes(byte[] bytes) {
        int y;
        
        for (int x=0;x<bytes.length;x++) {
            if (mti >= N)   // generate N words at one time
            {
                int kk;
                final int[] mt = this.mt; // locals are slightly faster
                final int[] mag01 = this.mag01; // locals are slightly faster
                
                for (kk = 0; kk < N - M; kk++) {
                    y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                    mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
                }
                for (; kk < N-1; kk++) {
                    y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                    mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
                }
                y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
                mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
                
                mti = 0;
            }
            
            y = mt[mti++];
            y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
            y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
            y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
            y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
            
            bytes[x] = (byte)(y >>> 24);
        }
    }
    
    
    @SuppressWarnings({"ConstantConditions"})
    public final long nextLong() {
        int y;
        int z;
        
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            for (; kk < N-1; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
            
            mti = 0;
        }
        
        y = mt[mti++];
        y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
        y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
        y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
        y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
        
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                z = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (z >>> 1) ^ mag01[z & 0x1];
            }
            for (; kk < N-1; kk++) {
                z = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (z >>> 1) ^ mag01[z & 0x1];
            }
            z = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (z >>> 1) ^ mag01[z & 0x1];
            
            mti = 0;
        }
        
        z = mt[mti++];
        z ^= z >>> 11;                          // TEMPERING_SHIFT_U(z)
        z ^= (z << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(z)
        z ^= (z << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(z)
        z ^= (z >>> 18);                        // TEMPERING_SHIFT_L(z)
        
        return (((long)y) << 32) + (long)z;
    }
    
    
    
    /** Returns a long drawn uniformly from 0 to n-1.  Suffice it to say,
     * n must be > 0, or an IllegalArgumentException is raised.
     * @param n max long
     * @return next long
     */
    @SuppressWarnings({"ConstantConditions"})
    public final long nextLong(final long n) {
        if (n<=0)
            throw new IllegalArgumentException("n must be positive");
        
        long bits, val;
        do
        {
            int y;
            int z;
            
            if (mti >= N)   // generate N words at one time
            {
                int kk;
                final int[] mt = this.mt; // locals are slightly faster
                final int[] mag01 = this.mag01; // locals are slightly faster
                
                for (kk = 0; kk < N - M; kk++) {
                    y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                    mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
                }
                for (; kk < N-1; kk++) {
                    y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                    mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
                }
                y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
                mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
                
                mti = 0;
            }
            
            y = mt[mti++];
            y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
            y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
            y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
            y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
            
            if (mti >= N)   // generate N words at one time
            {
                int kk;
                final int[] mt = this.mt; // locals are slightly faster
                final int[] mag01 = this.mag01; // locals are slightly faster
                
                for (kk = 0; kk < N - M; kk++) {
                    z = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                    mt[kk] = mt[kk+M] ^ (z >>> 1) ^ mag01[z & 0x1];
                }
                for (; kk < N-1; kk++) {
                    z = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                    mt[kk] = mt[kk+(M-N)] ^ (z >>> 1) ^ mag01[z & 0x1];
                }
                z = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
                mt[N-1] = mt[M-1] ^ (z >>> 1) ^ mag01[z & 0x1];
                
                mti = 0;
            }
            
            z = mt[mti++];
            z ^= z >>> 11;                          // TEMPERING_SHIFT_U(z)
            z ^= (z << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(z)
            z ^= (z << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(z)
            z ^= (z >>> 18);                        // TEMPERING_SHIFT_L(z)
            
            bits = (((((long)y) << 32) + (long)z) >>> 1);
            val = bits % n;
        } while (bits - val + (n-1) < 0);
        return val;
    }
    
    /** Returns a random double in the half-open range from [0.0,1.0).  Thus 0.0 is a valid
     * result but 1.0 is not. */
    @SuppressWarnings({"ConstantConditions"})
    public final double nextDouble() {
        int y;
        int z;
        
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            for (; kk < N-1; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
            
            mti = 0;
        }
        
        y = mt[mti++];
        y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
        y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
        y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
        y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
        
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                z = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (z >>> 1) ^ mag01[z & 0x1];
            }
            for (; kk < N-1; kk++) {
                z = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (z >>> 1) ^ mag01[z & 0x1];
            }
            z = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (z >>> 1) ^ mag01[z & 0x1];
            
            mti = 0;
        }
        
        z = mt[mti++];
        z ^= z >>> 11;                          // TEMPERING_SHIFT_U(z)
        z ^= (z << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(z)
        z ^= (z << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(z)
        z ^= (z >>> 18);                        // TEMPERING_SHIFT_L(z)
        
        /* derived from nextDouble documentation in jdk 1.2 docs, see top */
        return ((((long)(y >>> 6)) << 27) + (z >>> 5)) / (double)(1L << 53);
    }
    
    
    
    
    
    @SuppressWarnings({"ConstantConditions"})
    public final double nextGaussian() {
        if (__haveNextNextGaussian) {
            __haveNextNextGaussian = false;
            return __nextNextGaussian;
        } else {
            double v1, v2, s;
            do
            {
                int y;
                int z;
                int a;
                int b;
                
                if (mti >= N)   // generate N words at one time
                {
                    int kk;
                    final int[] mt = this.mt; // locals are slightly faster
                    final int[] mag01 = this.mag01; // locals are slightly faster
                    
                    for (kk = 0; kk < N - M; kk++) {
                        y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                        mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
                    }
                    for (; kk < N-1; kk++) {
                        y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                        mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
                    }
                    y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
                    mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
                    
                    mti = 0;
                }
                
                y = mt[mti++];
                y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
                y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
                y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
                y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
                
                if (mti >= N)   // generate N words at one time
                {
                    int kk;
                    final int[] mt = this.mt; // locals are slightly faster
                    final int[] mag01 = this.mag01; // locals are slightly faster
                    
                    for (kk = 0; kk < N - M; kk++) {
                        z = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                        mt[kk] = mt[kk+M] ^ (z >>> 1) ^ mag01[z & 0x1];
                    }
                    for (; kk < N-1; kk++) {
                        z = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                        mt[kk] = mt[kk+(M-N)] ^ (z >>> 1) ^ mag01[z & 0x1];
                    }
                    z = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
                    mt[N-1] = mt[M-1] ^ (z >>> 1) ^ mag01[z & 0x1];
                    
                    mti = 0;
                }
                
                z = mt[mti++];
                z ^= z >>> 11;                          // TEMPERING_SHIFT_U(z)
                z ^= (z << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(z)
                z ^= (z << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(z)
                z ^= (z >>> 18);                        // TEMPERING_SHIFT_L(z)
                
                if (mti >= N)   // generate N words at one time
                {
                    int kk;
                    final int[] mt = this.mt; // locals are slightly faster
                    final int[] mag01 = this.mag01; // locals are slightly faster
                    
                    for (kk = 0; kk < N - M; kk++) {
                        a = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                        mt[kk] = mt[kk+M] ^ (a >>> 1) ^ mag01[a & 0x1];
                    }
                    for (; kk < N-1; kk++) {
                        a = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                        mt[kk] = mt[kk+(M-N)] ^ (a >>> 1) ^ mag01[a & 0x1];
                    }
                    a = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
                    mt[N-1] = mt[M-1] ^ (a >>> 1) ^ mag01[a & 0x1];
                    
                    mti = 0;
                }
                
                a = mt[mti++];
                a ^= a >>> 11;                          // TEMPERING_SHIFT_U(a)
                a ^= (a << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(a)
                a ^= (a << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(a)
                a ^= (a >>> 18);                        // TEMPERING_SHIFT_L(a)
                
                if (mti >= N)   // generate N words at one time
                {
                    int kk;
                    final int[] mt = this.mt; // locals are slightly faster
                    final int[] mag01 = this.mag01; // locals are slightly faster
                    
                    for (kk = 0; kk < N - M; kk++) {
                        b = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                        mt[kk] = mt[kk+M] ^ (b >>> 1) ^ mag01[b & 0x1];
                    }
                    for (; kk < N-1; kk++) {
                        b = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                        mt[kk] = mt[kk+(M-N)] ^ (b >>> 1) ^ mag01[b & 0x1];
                    }
                    b = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
                    mt[N-1] = mt[M-1] ^ (b >>> 1) ^ mag01[b & 0x1];
                    
                    mti = 0;
                }
                
                b = mt[mti++];
                b ^= b >>> 11;                          // TEMPERING_SHIFT_U(b)
                b ^= (b << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(b)
                b ^= (b << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(b)
                b ^= (b >>> 18);                        // TEMPERING_SHIFT_L(b)
                
                /* derived from nextDouble documentation in jdk 1.2 docs, see top */
                v1 = 2 *
                        (((((long)(y >>> 6)) << 27) + (z >>> 5)) / (double)(1L << 53))
                        - 1;
                v2 = 2 * (((((long)(a >>> 6)) << 27) + (b >>> 5)) / (double)(1L << 53))
                - 1;
                s = v1 * v1 + v2 * v2;
            } while (s >= 1 || s==0);
            double multiplier = /*Strict*/Math.sqrt(-2 * /*Strict*/Math.log(s)/s);
            __nextNextGaussian = v2 * multiplier;
            __haveNextNextGaussian = true;
            return v1 * multiplier;
        }
    }
    
    
    
    
    
    /** Returns a random float in the half-open range from [0.0f,1.0f).  Thus 0.0f is a valid
     * result but 1.0f is not.
     * @return next float
     */
    public final float nextFloat() {
        int y;
        
        if (mti >= N)   // generate N words at one time
        {
            int kk;
            final int[] mt = this.mt; // locals are slightly faster
            final int[] mag01 = this.mag01; // locals are slightly faster
            
            for (kk = 0; kk < N - M; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            for (; kk < N-1; kk++) {
                y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
            }
            y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
            
            mti = 0;
        }
        
        y = mt[mti++];
        y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
        y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
        y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
        y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
        
        return (y >>> 8) / ((float)(1 << 24));
    }
    
    
    
    /** Returns an integer drawn uniformly from 0 to n-1.  Suffice it to say,
     * n must be > 0, or an IllegalArgumentException is raised. */
    @SuppressWarnings({"ConstantConditions"})
    public final int nextInt(final int n) {
        if (n<=0)
            throw new IllegalArgumentException("n must be positive");
        
        if ((n & -n) == n)  // i.e., n is a power of 2
        {
            int y;
            
            if (mti >= N)   // generate N words at one time
            {
                int kk;
                final int[] mt = this.mt; // locals are slightly faster
                final int[] mag01 = this.mag01; // locals are slightly faster
                
                for (kk = 0; kk < N - M; kk++) {
                    y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                    mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
                }
                for (; kk < N-1; kk++) {
                    y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                    mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
                }
                y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
                mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
                
                mti = 0;
            }
            
            y = mt[mti++];
            y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
            y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
            y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
            y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
            
            return (int)((n * (long) (y >>> 1) ) >> 31);
        }
        
        int bits, val;
        do
        {
            int y;
            
            if (mti >= N)   // generate N words at one time
            {
                int kk;
                final int[] mt = this.mt; // locals are slightly faster
                final int[] mag01 = this.mag01; // locals are slightly faster
                
                for (kk = 0; kk < N - M; kk++) {
                    y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                    mt[kk] = mt[kk+M] ^ (y >>> 1) ^ mag01[y & 0x1];
                }
                for (; kk < N-1; kk++) {
                    y = (mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK);
                    mt[kk] = mt[kk+(M-N)] ^ (y >>> 1) ^ mag01[y & 0x1];
                }
                y = (mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK);
                mt[N-1] = mt[M-1] ^ (y >>> 1) ^ mag01[y & 0x1];
                
                mti = 0;
            }
            
            y = mt[mti++];
            y ^= y >>> 11;                          // TEMPERING_SHIFT_U(y)
            y ^= (y << 7) & TEMPERING_MASK_B;       // TEMPERING_SHIFT_S(y)
            y ^= (y << 15) & TEMPERING_MASK_C;      // TEMPERING_SHIFT_T(y)
            y ^= (y >>> 18);                        // TEMPERING_SHIFT_L(y)
            
            bits = (y >>> 1);
            val = bits % n;
        } while(bits - val + (n-1) < 0);
        return val;
    }
    
    
    /**
     * Tests the code.
     * @param args arguments
     */
    @SuppressWarnings({"ConstantConditions"})
    public static void main(String args[]) {
        int j;
        
        MersenneTwisterFast r;
        
        // CORRECTNESS TEST
        // COMPARE WITH http://www.math.keio.ac.jp/matumoto/CODES/MT2002/mt19937ar.out
        
        r = new MersenneTwisterFast(new int[]{0x123, 0x234, 0x345, 0x456});
        System.out.println("Output of MersenneTwisterFast with new (2002/1/26) seeding mechanism");
        for (j=0;j<1000;j++) {
            // first, convert the int from signed to "unsigned"
            long l = (long)r.nextInt();
            if (l < 0 ) l += 4294967296L;  // max int value
            String s = String.valueOf(l);
            while(s.length() < 10) s = " " + s;  // buffer
            System.out.print(s + " ");
            if (j%5==4) System.out.println();
        }
        
        // SPEED TEST
        
        final long SEED = 4357;
        
        int xx; long ms;
        System.out.println("\nTime to test grabbing 100000000 ints");
        
        Random rr = new Random(SEED);
        xx = 0;
        ms = System.currentTimeMillis();
        for (j = 0; j < 100000000; j++)
            xx += rr.nextInt();
        System.out.println("java.util.Random: " + (System.currentTimeMillis()-ms) + "          Ignore this: " + xx);
        
        r = new MersenneTwisterFast(SEED);
        ms = System.currentTimeMillis();
        xx=0;
        for (j = 0; j < 100000000; j++)
            xx += r.nextInt();
        System.out.println("Mersenne Twister Fast: " + (System.currentTimeMillis()-ms) + "          Ignore this: " + xx);
        
        // TEST TO COMPARE TYPE CONVERSION BETWEEN
        // MersenneTwisterFast.java AND MersenneTwister.java
        
        System.out.println("\nGrab the first 1000 booleans");
        r = new MersenneTwisterFast(SEED);
        for (j = 0; j < 1000; j++) {
            System.out.print(r.nextBoolean() + " ");
            if (j%8==7) System.out.println();
        }
        if (!(j%8==7)) System.out.println();
        
        System.out.println("\nGrab 1000 booleans of increasing probability using nextBoolean(double)");
        r = new MersenneTwisterFast(SEED);
        for (j = 0; j < 1000; j++) {
            System.out.print(r.nextBoolean(j/999.0) + " ");
            if (j%8==7) System.out.println();
        }
        if (!(j%8==7)) System.out.println();
        
        System.out.println("\nGrab 1000 booleans of increasing probability using nextBoolean(float)");
        r = new MersenneTwisterFast(SEED);
        for (j = 0; j < 1000; j++) {
            System.out.print(r.nextBoolean(j/999.0f) + " ");
            if (j%8==7) System.out.println();
        }
        if (!(j%8==7)) System.out.println();
        
        byte[] bytes = new byte[1000];
        System.out.println("\nGrab the first 1000 bytes using nextBytes");
        r = new MersenneTwisterFast(SEED);
        r.nextBytes(bytes);
        for (j = 0; j < 1000; j++) {
            System.out.print(bytes[j] + " ");
            if (j%16==15) System.out.println();
        }
        if (!(j%16==15)) System.out.println();
        
        byte b;
        System.out.println("\nGrab the first 1000 bytes -- must be same as nextBytes");
        r = new MersenneTwisterFast(SEED);
        for (j = 0; j < 1000; j++) {
            System.out.print((b = r.nextByte()) + " ");
            if (b!=bytes[j]) System.out.print("BAD ");
            if (j%16==15) System.out.println();
        }
        if (!(j%16==15)) System.out.println();
        
        System.out.println("\nGrab the first 1000 shorts");
        r = new MersenneTwisterFast(SEED);
        for (j = 0; j < 1000; j++) {
            System.out.print(r.nextShort() + " ");
            if (j%8==7) System.out.println();
        }
        if (!(j%8==7)) System.out.println();
        
        System.out.println("\nGrab the first 1000 ints");
        r = new MersenneTwisterFast(SEED);
        for (j = 0; j < 1000; j++) {
            System.out.print(r.nextInt() + " ");
            if (j%4==3) System.out.println();
        }
        if (!(j%4==3)) System.out.println();
        
        System.out.println("\nGrab the first 1000 ints of different sizes");
        r = new MersenneTwisterFast(SEED);
        int max = 1;
        for (j = 0; j < 1000; j++) {
            System.out.print(r.nextInt(max) + " ");
            max *= 2;
            if (max <= 0) max = 1;
            if (j%4==3) System.out.println();
        }
        if (!(j%4==3)) System.out.println();
        
        System.out.println("\nGrab the first 1000 longs");
        r = new MersenneTwisterFast(SEED);
        for (j = 0; j < 1000; j++) {
            System.out.print(r.nextLong() + " ");
            if (j%3==2) System.out.println();
        }
        if (!(j%3==2)) System.out.println();
        
        System.out.println("\nGrab the first 1000 longs of different sizes");
        r = new MersenneTwisterFast(SEED);
        long max2 = 1;
        for (j = 0; j < 1000; j++) {
            System.out.print(r.nextLong(max2) + " ");
            max2 *= 2;
            if (max2 <= 0) max2 = 1;
            if (j%4==3) System.out.println();
        }
        if (!(j%4==3)) System.out.println();
        
        System.out.println("\nGrab the first 1000 floats");
        r = new MersenneTwisterFast(SEED);
        for (j = 0; j < 1000; j++) {
            System.out.print(r.nextFloat() + " ");
            if (j%4==3) System.out.println();
        }
        if (!(j%4==3)) System.out.println();
        
        System.out.println("\nGrab the first 1000 doubles");
        r = new MersenneTwisterFast(SEED);
        for (j = 0; j < 1000; j++) {
            System.out.print(r.nextDouble() + " ");
            if (j%3==2) System.out.println();
            
        }
        if (!(j%3==2)) System.out.println();
        
        
        System.out.println("\nGrab the first 1000 gaussian doubles");
        r = new MersenneTwisterFast(SEED);
        for (j = 0; j < 1000; j++) {
            System.out.print(r.nextGaussian() + " ");
            if (j%3==2) System.out.println();
        }
        if (!(j%3==2)) System.out.println();
        
    }
}
